Cycle-air pervious drum-type drier

ABSTRACT

This invention is directed to an enclosed drum dryer for textile webs that includes a plurality of air-pervious dryer drums alternately arranged in offset upper and lower banks. The outer surface of each drum receives heated air through high velocity nozzle slots in an associated pressure chamber that is connected to a pair of fans. The enclosure is maintained under negative pressure by an exhaust fan. Each offset pair of dryer drums in effect has its own air circulation system.

United States Patent [72] Inventor Frank Catallo 187 Wellington Ave., Elmont, N.Y. 11003 [21] Appl. No. 804,745 [22] Filed Mar. 6, 1969 [45] Patented June 1, 1971 [54] CYCLE-AIR PERVIOUS DRUM-TYPE DRIER 6 Claims, 4 Drawing Figs.

[52] U.S.C1 34/115 [51] Int. Cl .1 F26b 11/02 [50] Field of Search 34/114,

[56] References Cited UNITED STATES PATENTS 1,565,494 12/1925 Patterson 34/92 2,301,249 11/1942 Butterworth... 3,473,236 10/1969 Fleissner Primary Examiner-Frederick L. Matteson Assistant Examiner-Harry B. Ramey Attorney-F. .1 Pisarra ABSTRACT: This invention is directed to an enclosed drum dryer for textile webs that includes a plurality of air-pervious dryer drums alternately arranged in offset upper and lower banks. The outer surface of each drum receives heated air through high velocity nozzle slots in an associated pressure chamber that is connected to a pair of fans. The enclosure is maintained under negative pressure by an exhaust fan. Each offset pair of dryer drums in effect has its own air circulation system.

PATENTEDJUN usn 3581M 411 SHEET 1 [IF 2 VILN'I up; FRANK CATAL HAM AT TORNEY PATENTEDJUN 1197! 3,581,411

SHEET 2 0F 2 INVEN'IUR FRANK CATALLO ATTORNEY CYCLE-AIR PERVIOUS DRUM-TYPE DRIER This invention relates generally to new and useful improvements in drying equipment for sheet materials and particularly seeks to provide a novel enclosed drum type of dryer for a continuous web of fabric.

The art of drying textiles is of course as old as the production of textiles, whether by weaving, knotting or knitting. Basically, there are four ways in which textiles may be dried; (1) air drying on rope or other fixed supports; (2) festoon drying in which the fabric is looped over a series of conveyor slats in a drying room or chamber; (3) conveyor drying in which the fabric is supported as a flat web on a continuous conveyor; and (4) drum drying in which the fabric progresses alternately over and under a series of air-pervious cylinders while exposed to heated air within a chamber.

This invention specifically relates to the latter type of drying equipment.

Therefore, an object of this invention is to provide an enclosed dryer for a continuous fabric web that includes a plurality of alternating high and low air'pervious drums each of which is supplied by air from a nozzled pressure chamber substantially surrounding about half of its associated drum.

Another object of this invention is to provide a dryer of the character stated in which the air circulating through each drum is heated by an internally positioned, externally controlled gas burner.

Another object of this invention is to provide a dryer of the character stated in which air is supplied to each pressure chamber by a pair of externally driven blowers located adjacent the ends thereof and arranged so that the intake air for one pair of blowers is provided by the outlet air from another pair of blowers after having passed through an intervening dryer drum.

Another object of this invention is to provide a dryer of the character stated in which a top exhaust fan is located above each lower dryer drum at a position intermediate the blowers for an adjacent upper dryer drum.

A further object of this invention is to provide a dryer of the character stated, that has a drying capacity on the order of double that of currently available competitive equipment of substantially the same size.

A further object of this invention is to provide a dryer of the character stated that is simple in design, rugged in construction and economical to manufacture.

With these and other objects, the nature of which will be apparent, the invention will be more fully understood by reference to the drawings, the accompanying detailed description and the appended claims.

In the drawings:

FIG. 1 is a side elevation, partly in section, of a drum dryer constructed in accordance with this invention;

FIG. 2 is a top plan view thereof, partly in section;

FIG. 3 is an end elevation thereof; and

FIG. 4 is a transverse vertical section taken along line 4-4of FIG. 1.

Referring to the drawings in detail, it will be seen that the invention, as illustrated, is embodied in an enclosed dryer that includes a bottom 5, insulated sidewalls 6,6, insulated end walls 7,7 and an insulated top 8.

A plurality (4 in the illustrated embodiment) of transverse open-ended air-pervious dryer drums 9, each having a wire mesh surface 10, are rotatably supported by suitable means between the sidewalls 6,6 and are arranged in staggered pairs offset at approximately 45 so that there are two upper and two lower drums.

Each drum 9 is individually driven by an external variable speed drive, as indicated at 11, so that proper control of the tension of the web may be maintained as it passes through the dryer.

The top half of each of the upper drums 9 and the bottom half of each of the lower drums 9 are covered by a housing 12 (see FIGS. 1 and 2) that defines a pressure chamber 13 and includes a generally semicylindrical plate or shell 14 concentric with and slightly spaced from its associated drum. Each shell 14 is provided with a multiplicity of nozzle slots 15 through from the pressure chamber 13.

Air is supplied to each pressure chamber 13 by a pair of fans 16,16 located just inside the sidewalls 6 and individually driven by external motor drives, schematically indicated at 17. The fans 16 are arranged so that the discharge from the lower fans enters their associated pressure chambers from the right (as viewed in FIG. I) and the discharge from the upper fans enters their associated pressure chambers from the left. In this manner intake air for each pair of lower fans is supplied from an upper pressure chamber 13 through its associated upper drum 9, and intake air for each pair of upper fans is supplied from a lower pressure chamber 13 through its associated lower drum 9. The arrows in FIGS. 1 and 4 indicate the general nature of the airflow through each pair of upper and lower drums and the associated fans and pressure chambers.

The air circulating through the dryer is heated by gas burners, indicated 18, supported within the drums 9 and preferably arranged so that the burners for each pair of upper and lower drums has a common supply pipe 19 connected to the usual mixer regulator (not shown). Furthermore, in order to prevent flame failure, it is preferable to have the flames from the burners 18 in the upper drums 9 directed downwardly and those in the lower drums 9 directed upwardly, that is to say, generally in the direction of airflow.

Fan-fitted exhausts 20, located centrally of the top 8 over each of the lower drums 9, are provided to withdraw moist air from the dryer and to keep the interior of the dryer under a negative pressure. Fresh air may be admitted at any convenient location, as through the entrance of the dryer and through suitably located inlet openings such as 23 in the dryer end walls (see FIG. 3). In operation, a wet fabric web is led from a previous processing unit into a pair of draw rolls 21,21 at the entrance end of the dryer, thence alternately under and over the successive lower and upper drums 9 and the dried web is discharged through a pair of draw rolls 22,22 at the exit end of the dryer. The rotational speeds of the drums 9 are adjusted to compensate for the shrinkage of the fabric, as it dries, or to permit bulking" of the fabric between successive drums, as may be required when drying stretch type fabrics.

The fabric web is always kept under proper control as it passes around the successive drums 9 as a result of the unique air circulating system by which the interior of the dryer is kept under a generally negative pressure, thus causing the fabric to be sucked onto the surfaces of the drums, and by which the fabric is simultaneously blown onto the surfaces of the drums by the air passing from the pressure chambers 13 through the nozzle slots 15.

Low maintenance of the dryer is assured because all driving mechanisms for the various moving parts, i.e. the drums and fans, are located externally and thus are not subjected to heat degradation.

It is of course to be understood that. variations in arrangements and proportions of parts may be made within the scope of the appended claims.

lclaim:

1. A dryer for a continuously moving fabric web including, an enclosure having top, bottom, side and end walls, a lower transverse air-pervious dryer drum rotatably supported between said sidewalls, an upper transverse air-pervious dryer drum rotatably supported between said sidewalls in a location offset with respect to said lower dryer drum, means for rotating said dryer drums, at lower transverse housing located beneath said lower dryer drum and having a generally semicylindrical slotted shell concentric with and slightly spaced from the lower portion of said lower dryer drum, an upper transverse housing located above said upper dryer drum and having a generally semicylindrical slotted shell concentric with and slightly spaced from the upper portion of said upper dryer drum, said transverse housings each defining a pressure chamber, a lower fan for drawing air from said upper pressure chamber through said upper dryer drum and discharging said air into said lower pressure chamber under pressure, an upper fan for drawing air from said lower pressure chamber through said lower dryer drum and discharging said air into said upper pressure chamber under pressure, means for operating said fans, means for heating the air circulating within said enclosure, and means for exhausting moist air from the top of said enclosure, said exhaust means being effective to maintain a negative pressure within said enclosure.

2. The dryer of claim 1 additionally including at least one additional pair of upper and lower dryer drums together with the said pressure chamber-defining housing and fans therefor, said additional dryer drums, housing and fans being arranged 

1. A dryer for a continuously moving fabric web including, an enclosure having top, bottom, side and end walls, a lower transverse air-pervious dryer drum rotatably supported between said sidewalls, an upper transverse air-pervious dryer drum rotatably supported between said sidewalls in a location offset with respect to said lower dryer drum, means for rotating said dryer drums, a lower transverse housing located beneath said lower dryer drum and having a generally semicylindrical slotted shell concentric with and slightly spaced from the lower portion of said lower dryer drum, an upper transverse housing located above said upper dryer drum and having a generally semicylindrical slotted shell concentric with and slightly spaced from the upper portion of said upper dryer drum, said transverse housings each defining a pressure chamber, a lower fan for drawing air from said upper pressure chamber through said upper dryer drum and discharging said air into said lower pressure chamber under pressure, an upper fan for drawing air from said lower pressure chamber through said lower dryer drum and discharging said air into said upper pressure chamber under pressure, means for operating said fans, means for heating the air circulating within said enclosure, and means for exhausting moist air from the top of said enclosure, said exhaust means being effective to maintain a negative pressure within said enclosure.
 2. The dryer of claim 1 additionally including at least one additional pair of upper and lower dryer drums together with the said pressure chamber-defining housing and fans therefor, said additional dryer drums, housing and fans being arranged in series with respect to said first described dryer drums, housing and fans.
 3. The dryer of claim 1 in which two fans are provided for each of said pressure chamber-defining housings.
 4. The dryer of claim 2 in which two fans are provided for each of said pressure chamber-defining housings.
 5. The dryer of claim 4 in which means located externally of said enclosure are provided for independently rotating each of said dryer drums.
 6. The dryer of claim 5 in which said fan operating means are located externally of said enclosure. 